Piston ring



L.. G. LYMAN PISTON RING Sept. 16, 1930.

Fi-led Aug. 20, 1927 lllH .l www .w

Patented Sept. 16, 1930 LEW e. Lm, or PHILADELPHIA, PENNSYLVANIA rrsToN me Application led August 20, 192.7. Serial No. 214,359.

' My invention relates to improvements in packing or piston rings for pistons and cylinders whereby a more perfect packing is secured between the ressure chamberl and 'piston, asv for exarnp e, inthe well known in-` ternal combustion engine to which my ring is particularly adapted, and at the same time maintaining suitable lubrication and mini-` mum ofwear. It is more particularly adapt- -ed to that class of rings wherein a spring is employed to compress the ring on its seat and also act by torsion to expand the ring.

It is within the lprovince of the disclosure to improve generally and to enhance the util- 16 ity and safety of the operation of that class of device to which the invention relates.

In piston rings of this class it is customary practice to cut an annular groove on the inner periphery of the ring to accommodate a.

20 spring ire coacting with the walls of the piston groove forces the ring downward on its seat and at the same time outward against the walls of the c lindern In the installatlon of the spring and ring to the piston there is grave danger of' the spring ends coming out of the slot channel and wedging itself between the piston and the wall of the cylinder. The wire is usually constructed of hard spring steel whichr 0bviously will cut and score the cylinder walls if operated in that position. The first object of my invention is to provide a novel construction of the groove in the piston ring wherein the spring may be positively and Securely positioned so that the, dan er of it coming out of place` during instaation is eliminated. In rings `of the type aforesaid the constant reciprocating movement of the ring will cause the same to rock or turn within the confining channel area, thereby destroying its function. The second object of my invention-is to provide a novel structure that will keep the ring securely on its seat.v

A further .and third object of my invention is to provide a ring that will not chatter or become noisy in its operation, or to allow the vacuum on the downward stroke of the piston to draw oil past the rings into the combustion chamber.

A fourth object of my invention is to propiston ma vide a piston rin that will not collect oil on the upward stro e of the piston and will clean the cylinder walls on the downward stroke; and to rovide other improvements as will hereina ter appear. v

f With these objects in view lmy present invention consists of a novel construction and arrangement of parts as will hereinafter be more fully described and pointed out in the claim, reference being had to the accompanying drawing/forming part of the specification and in which; Fig. 1 is a sectional lan of Fig. 2 on a line .1-1, showing 'a cylin er with its piston and rings; Fig. 2 is a. section on line 2-2 of Figure 1 showing a piston of any well known internal combustlon engine vwhere the piston is provided with a piston ring and adapted to operate withinthe cylinder which is drawn in section; Fig. 3 is a section on line 3--3of Figure 1 and shows more clearl)7 the position ofthe spring and its retaining groove in relation to the ring and the cylinder Wall; Fig. 4 is a sect-ion on line 4-4 of Figure 1, showing a section of the ring through itsv solid structure; .and Fig. 5 shows a part of the sinuous sprin and more particularlyy the flat portion at tie loops or apexes. In said figures similar numerals of reference refer to similar parts throughout the several views. The`numeral 1 designates the walls of the cylinder through which the piston 2 is adapted to reciprocate. In order that the reciprocate lfreely within the said cylin er a pedetermined clearance between the wallsof the cylinder and the piston must be maintained and in order to prevent the escape of the explosive pressure createdon top of the piston or the passage of oil from the bottom of the crank case to the top of the piston, the piston ring'3 is provided. The said ring 3 is adapted to engage in a suitable annular channel 4 provided in the piston 2. The said ring 3 is provided with a break 8 in its annular continuity to allow it to expand over the top of'the piston and into the annular channel 4. This is known as a step cut The numeral 5 designates an annular acute angle groove disposedin the inner surface of titl the rin 3, one leg of the angle extends substantia ly vertically downward from the top of the ring to a point below the center of gravity of the said ring. The other leg of the angle extends upwardly to the inner periphery of the ring forming an acute angle. The said angular groove does not extend the entire circumference of the ring 3 but starts.

and terminates a predetermined distance from the break, the portion intervening presenting substantially a solid cross section. The numeral 6 designates a spring of resilient wire formed into asinuous curve, the loops or apexes being of a flat surface. The said spring 6 is positioned within the ring slot 5 and inclined to the axis of the ring so that part of the sprin is enclosed in the groove and part extends tierebeyond and inside the area of said ring channel so that a pressure is exerted by the spring on the piston ring to force it against the lower bearing surface of the ring channel, and outwardly to expand the ring against the cylinder wall. The upper outer periphery of the ring 3 is chamfered at 7 so that upon the upward stroke of the piston it will allow the oil on the cylinder wall to pass by the piston, but on the downward strolre a cutting edge is presented which scrapes the surplus oil from the wall of the cylinder and drains the same back hinto the crank case. Having thus described the varions parts throughout the several views its inode of operation will be substantially 'as `lollows all of which will be readily understood by those skilled in the art to which this invent-ion relates.

ln applying the piston ring to the piston the sinuons spring is placed in the ring groove slot and the ring is expanded and placed in the annular channel at the saine time the spring is compressed so that it enters the channel behind the ring. During this opera= tion the ends ot the spring abut against the ends of the angular groove in the ring thereby preventing the wire from creeping out and over the top of the ring whichif not corrected would score and eventually destroy the inner wall ol' the c linder. ln the normal opera- Vtion of the piston should the piston ring be not rmly seated the vacuum on the downward stroke would raise therin 0E its seat which allows oil to be drawn un erneath and into the annular channel back of the ring, whereupon the upward strolre oil is forced over the top of lsaid ring from behind the ring upward into the combustion chamber. The sinuous spring, however, being inclined to the axis of the ring forms a positive pres`1 sure which keeps the rin on its seat and firmly against the walls of t e cylinder thus preventing the above condition. l prefer to provide a dat surface' at the top of the loops of the spring 6 so that the constant motion will not wear a depression in the Contact places which would be the case should the loops tex;-

minate in a sharp oint. The constant motion would also wear t e spring at its apexes and cause unseasonable breakage.

Durin the reci rocatin motion of the piston the c amfered edge al ows the iston to ride over the oiled surface but on t e downward stroke the cutting edge of the rin scrapes the surplus oil awa The frictions. contact between the wall o? the cylinder and the outer surface of the piston ring will cause the ring to rock or have a tendency to revolve within the annular channel. This is apparent in this type of ring dueto the fact that the upper ring surface 1s smaller in area than the lower or seating surface. To overcome this defect I position the apex of the angular slot well below the center. of gravity of the ring and in this manner the tendency of rockin is eliminated, thus accomplishing the second object of my said invention.

l do not wish to limit myself to the exact construction as shown as it is obvious that certain departures can be made therefrom without departing from the spirit and intent of my said invention, but what I claim as new and desire to secure by Letters Patent is The combination of a piston having an annular channel, a circumferentially discontinuous piston ring therein, a groove in the inner periphery of said ring having a wall parallel to cylinder-engaging surface of the ring, and a wire-like, slnuous sprin apexee of which engage said parallel wal of said groove adjacent the lower edge thereof and alternate apexes of which engage said channel adjacent the top thereof.

In testimony whereof l aliix my signature.

LEW G. LYMAN. 

